Method of recovering graphite from worn-out crucibles.



ALBERTlTEICI-IMANN, OF ZEITZ, GERMANY.

METHOD OF REGOVE-RING GRAPHITE FROM WORN-OUT CRUCIBLES.

No Drawing.

Specification of Letters Patent.

Application filed November 5, 1912. Serial No. 729,642.

To all whom it may concern Be it known that I, ALBERT TEICHMANN, a subject of the Emperor of Germany, and a resident of Zeitz, in Saxon'y, Germany, have invented a new and useful Improvement in Methodsof Recovering the Graphite from Torn-Out Crucibles, of which the following is a specification.

The valuable graphite contained in worn out broken crucibles has up to now gone to waste, because no practical and econonncal ."process to recover it was known. Thisu'seful eifect may now be attained by the method which forms the subject matter of the present invention and is carried out as follows: The worn out crucibles are broken 'into pieces having the size of, perhaps, a

' fist, and these-pieces are subjected for from four to twelve hours, to the action of sulfuric, muriatic or, nitric acid, or-an-y other equivalent acid as may be best suited to the e composition of matter of which the respective crucibles were made, the object. of this treatment being to break the union between the Igraphite, which is one of the components of t at. composition of matter and the other components of the same. The thus treated pieces, are heated to red heat in a suitable furnace, -kiln,'retort, or the like, in order to evaporate the acid and ,to render the pieces rather brittle and. friable. Thereafterthe pieces arepassed between the roll ers of a. crushing mill for the purpose of loosening the slack, which then is separated from the crushed pieces by a sieve or the like. It will be understood that where the Word slack is used in this specification and in the claims comprised herein, that I means to include in said word substances ordinarily usedin the manufacture] of graphite crucibles such as binding materials which are other than graphite. The remaining pieces are subjected repeatedly and for as long a time as possible to the action of a grinding mill and the product obtained'by each grinding operation is sieved, this procedure being carried through in such a manner that a plurality of sizes of grain and of graphite dust, for instance six sizes of grain and twdsorts of dust are obtained.

. It is'of great importance that the rollers of the grindin mill rotate with absolutely the same sp even the very small differonce which is brought about by one tooth product of the more or less of the cog wheels, or by unusual spaces between the teeth of the cog wheels impairs the quality of the product to a remarkable degree. It is therefore preferable either to employ cog wheels of exactly the same number of teeth, or to impart power only to one of the rollers and to let this roller rotate the other one merely by the friction produced by the grinding action.

What I claim as-new and desire to secure by Letters Patent is:

1.' The method of recovering the graphite fromworn out, broken crucibles, consisting in subjecting the crucible pieces to the action'of an acid adapted to loosen the'union between the graphite in said pieces and the other component substances of the same; heating the thus-treated pieces to a glowing temperature; crushing them so as to loosen the slack; separating the slack from the crushed pieces; and grinding the latter.

2. The method of recovering the graphite,

from worn out broken crucibles, consisting in subjecting the crucible pieces to the action .of sulfuric acid; heating the thus treated pieces to .a glowing temperature; crushing them so as to loosen the slack; separating the slack from the crushed pieces; and grinding the latter.

3. The method of recovering the graphite from worn out broken crucibles consisting in subjecting the crucible pieces to the action of a mineral acid, heating the thus treated pieces to a glowing temperature, crushing them so as to loosen the slack, separating the slack from the crushed pieces and grinding the latter. e

4. The method of recovering the graphite from worn. outbroken crucibles, "consisting in subjecting the'crucible pieces to the'a'etion of a mineral acid 'for a'number of hours,

heating the thus treated piecesto red heat, crushing them so as to loosen 'the slack, separating the slack from thecrushed pieces, grinding the latter, and separating the grinding process into grains and dust. f

In testimon whereof I aflix my signature in presence 0 two witnesses.

. ALBERT TEICHMANN. Witnesses: a

WULDEMAR HAUPT, HnNRyfHAsPnn,

Patented Dec. 2. 1913. 

